High current carbon arc lamps or devices



July 26, 1960 w. ZAGIEBOYLO ETAL 2,946,916

HIGH CURRENT CARBON ARC LAMPS OR DEVICES Filed Sept. 10, 1958 INVENTORS Walter za iie y Bernard MC QUQ BY w%/ ATTORNEY United States Patent "cc HIGH CURRENT CARBON ARC LAMPS OR DEVICES Walter Zagieboylo, Norfolk, and Bernard McQue, Framingham, Mass., assignors to the United States of America as represented by the Secretary of the Army Filed Sept. 10, 1958, Ser. No. 760,280

9 Claims. (Cl. 314-49) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein, if patented, may be manufactured by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

The present invention relates to improvements in high current carbon arc lamps or devices. More particularly, it relates to means for insulating the carbon anode from its obturator to prevent arcing between the negative carbon electrode and the metal obturator.

The high current carbon arc lamp is believed to provide the best source of high temperature radiation now available for use in the study of the behavior of materials when exposed to extremely high temperature radiation. Accordingly, it is now being used to evaluate various materials and systems for combining materials for use in protecting the human body as well as equipment, in case of exposure to extremely high temperature radiation resulting from atomic and thermonuclear explosions.

The present improved high current carbon arc lamp is also especially useful in studying the effects of high intensity thermal radiation on materials and/or animal bodies.

One of the disadvantages of presently-available arc lamps, including the well-known Beck arc, is their limitation with respect to the input of electrical energy and consequent limitation in the output of light. This is due to the fact that above a certain input of electrical energy, the arc had a tendency to jump from the tip of the negative carbon electrode to the metal obturator or watercooled head in which the carbon anode is held, thus causing sputtering, lower light intensity, and eventual destruction of the metal obturator. Consequently, the input of electrical energy has had to be kept down to avoid too rapid destruction of the metal obturator.

It is, therefore, one of the important objects of the present invention to provide an improved insulated metal obturator or water-cooled head for a high current carbon arc lamp which eliminates the customary arcing between the negative carbon electrode and'the metal obturator while permitting good heat transfer.

Another object of the invention is to provide an improved insulated metal obturator or water-cooled head in which the carbon anode held by the obturator will be cooled adequately by the water circulating through said obturator to allow operation of the carbon arc lamp at high current levels without the danger of arcing.

A further object of the invention is to provide an obturator in the nature of a self-contained water-cooled jacket which is insulated electrically from a carbon anode; another object being to increase the normal life of the water-cooled obturator.

Another object of the invention is to provide improved sleeve-like insulating means for use in an obturator of a high current are lamp.

The foregoing and other objects and advantages of the present invention will appear from the following description and appended claims when considered in conjunction with the accompanying drawing forming a 2,946,916 Patented July 26, 1960 part of this specification wherein like reference characters designate corresponding parts in the several views.

In said drawing:

Fig. l is a perspective view of a high current are lamp embodying the present invention;

Fig. 2 is a front elevation of the insulated water-cooled obturator for the anode carbon electrode;

Fig. 3 is a rear elevation of the obturator of Fig. 2;

Fig. 4 is a slightly enlarged vertical sectional view taken substantially along the line 4-4 of Fig. 2, looking in the direction of the arrows; and

Fig. 5 is an enlarged fragmentary detail sectional view showing the relationship of the insulating means and obturator or water-cooled head.

Referring now particularly to the drawing, Fig. 1 shows in perspective a high current carbon arc device or lamp 10 embodying the present invention, and comprising an upright standard 11 supporting a water-cooled head or obturator 12 having a positive electrode or carbon anode 13. A bracket 14 is attached to and supported by the standard 11 and provides means for supporting a second water-cooled head 15 having a negative electrode'or carbon cathode 16. The head, or obturator 12 is removably mounted upon an upright support 9 by means of screws or bolts 8 which pass through holes 7 in the flange 12a of head 12.

Fig. 4 shows hollow head 12 with its cooling water chamber and in Figs. 2 and 3 head nipples 17 and 18 are shown. Nipples 17 and 18 are connected to water pipe lines 19 and 20, respectively (Fig. l) for supplying cooling Water to the hollow head 12.

In addition to being hollowed out to provide the water chamber shown, the head 12 is drilled out to provide a preferably centrally disposed cylindrical bore 21 to receive an electrical and heat-insulating sleeve-like member, shown as a whole at 22. This member 22 is of composite construction, consistin got a sleeve or cylinder 23 of temperature resistant ceramic material, such as Alundum which has a coating 24 on its exterior surface of copper. The copper coating 24 may be applied by placing the ceramic cylinder 23 in a vacuum chamber of a vaporizing apparatus (not shown) to apply evaporated copper to said exterior surface. The evaporated coating of copper is made dense enough to permit a plating operation to be effected so as to increase the exterior coating of copper 24, thus producing the insulator 22 in the form of the ceramic tube 23 with its integrated copper coating 24, see particularly Fig. 5.

The insulator 22 is inserted into the bore 21 of head or obturator 12 and is preferably silver-soldered at its opposite ends at 25 and 26 (see Fig. 4) to thus make a water-tight seal for head 12. In use, the ceramic-tocopper bond does not materially affect the cooling rate and is effective in electrically insulating the carbon anode 13 from the remainder of the water-cooled head.

By reason of the present invention, arcing between the negative carbon electrode 16 and the metal obturator 12, which holds and cools the carbon anode 13, is practically eliminated, thus enabling the operation of the carbon arc device or lamp 10 at a high electrical power input without danger to the cooling system or destruction of the obturator by arcing.

Obviously, the invention is not limited to the embodiments herein shown and described, but may assume other forms.

We claim:

1. A high current carbon arc device, comprising a water-cooled head for the negative carbon electrode, a negative carbon electrode in said head, a water-cooled second head for the positive carbon electrode, a positive carbon electrode in said second head, each of said heads having a central passage therein for the reception and feeding of the carbon electrodes, and a tubular sleeveformed of ceramic material having a coating of copper on its exterior surface, said sleeve being disposed in the central passage of the positive head between the passage Wall and the positive carbon electrode, said tubular sleeve being fixed in the passage by metallic cement in the joint between the sleeve and the adjacent wall of thepassage at both ends of the sleeve to provide a Water-tight seal for the head.

2. An article of manufacture comprising a water-cooled metal head for the positive carbon stick of a high current carbon arc device, said head having a centrally disposed cylindrical bore therein for the reception and feeding of the carbon stick, and an insulating sleeve disposed in said cylindrical bore between the wall thereof and the carbon stick, said sleeve having a copper exterior surface coating extending throughout its full length and being silver-soldered in position at opposite ends to said head in said bore so as to provide a water-tight seal for the head.

3. An article of manufacture comprising a watercooled obturator for the carbon anode of a high current carbon arc lamp, said obturator having a centrally disposed bore to receive said anode, a carbon anode in the bore, and a sleeve-like ceramic insulator disposed in said bore between the anode and the wall of the bore, said insulator having an exterior integrated metallic coating extending from end to end thereof.

4. A high current carbon arc lamp, comprising a watercooled head for the negative carbon electrode, a negative carbon electrode in said head, a Water-cooled second head for the anode carbon electrode, a carbon anode in said second head, each of said heads having a centrally disposed bore therein for the reception of the carbon electrodes, and a tubular sleeve formed from ceramic material having a coating of metal on its exterior surface, said sleeve being disposed in the bore of the second head between the wall of the bore and the carbon anode, said tubular sleeve being fixed in said bore by metallic cement in the joint between the sleeve and the adjacent wall of the bore at opposite ends of the sleeve to provide a watertight seal for the head.

5. A high current carbon arc lamp, comprising a watercooled head for the negative carbon electrode, a watercooled second head for the carbon anode, each of said heads having a centrally disposed bore therein for the reception of the carbon electrodes, and a tubular insulator sleeve formed from ceramic material having a copper coating on its exterior surface disposed within the bore of said second head.

6. A high current carbon arc lamp, comprising a watercooled head for the negative carbon electrode, a watercooled second head for the carbon anode, each of said heads having a centrally disposed bore therein for the reception of the carbon electrodes, and a tubular insulator sleeve formed from ceramic material having a copper coating on its exterior surface and silver soldered in position in the bore to provide a water-tight seal for said second head.

7. A high current carbon arc lamp, comprising a watercooled head for the carbon cathode, a water-cooled second head for the carbon anode, each of said heads having a drilled bore therein for the reception of the carbon electrode, and a tubular insulator sleeve formed from non-metallic material having a metal coating on its exterior surface disposed within the bore of said second head and soldered in position therein to provide a watertight seal for said head.

8. A water-cooled metal head for the positive carbon electrode of a high current carbon arc device, said head having a cylindrical bore formed therein for the reception of the positive carbon electrode, and a non-metallic insulator sleeve having an exterior surface coating of metal, said sleeve lining said bore and soldered in position therein to provide a water-tight seal for the head.

9. That improvement in the art of high current are lamps which includes a Water-cooled head having a cylindrical bore formed therein, of a sleeve-like insulator having a length corresponding to that of the bore for insertion in said bore and to be disposed wholly within the same, said insulator comprising a ceramic body portion and an integrated exterior coating of copper extending throughout the entire length of said ceramic body portion, and said insulator being located in cooperative relation with the head and in contact with the entire inner surface of said head bore.

References Cited in the file of this patent UNITED STATES PATENTS 2,434,555 Fischer et al Jan. 13, 1948 UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 2,946,916 July 26, 1960 Walter Zagie-boylo et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent. should read as corrected below.

Column 2, line 37, for "consistin gof" read consisting of column 3, line 18, strike out "in position"; line 19 before "said" insert position in Signed and sealed this 12th day of September 1961.

(SEAL) Attest:

ERNEST w. SWIDER DAVID L. LADD Commissioner of Patents Attesting Officer U SCOM M-DC- UNITED STATES PATENT OFFICE CERTIFIQATE -OF CORRECTION Patent No. 2,946,916 July 26 1960 Walter Zagie-boylo et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said'Letters Patent. should read as "corrected below.

Column 2, line 37, for "consistin gof" read consisting of column 3, line 18, strike out "in position"; line 19 before "said" insert position in Signed and sealed this 12th day of September 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Commissioner of Patents Attesting Officer USCOMM-DCE 

